class Solution {
public:
    vector<vector<int>> generate(int numRows) {
          vector<vector<int>>  vv;
          vv.resize(numRows);
          for(int i=0;i<vv.size();++i)
          {
              vv[i].resize(i+1,0);
              vv[i][0]=vv[i][vv[i].size()-1]=1;
          }

          for(int i=0;i<vv.size();++i)
          {
              for(int j=0;j<vv[i].size();++j)
              {
                  if(vv[i][j]==0)
                  {
                    vv[i][j]=vv[i-1][j]+vv[i-1][j-1];
                  }

              }
          }
          return vv;
    }
};
